Researchers at Maastricht University’s teaching hospital say that the Delta variant of coronavirus is around four times as infectious as the original version which originated in China.

American health institute CDC recently described the Delta variant as ‘as infectious as chicken pox’ in an international document reported on by the New York Times. And one recent study even suggested that respiratory samples from people infected with the Delta variant can harbour up to 1000 times higher viral loads compared to variants that are more closely related to the original Wuhan strain.

The Maastricht research is based on the viral load in 16,185 samples taken from people in southern Limburg in three distinct time periods. Samples taken between December 2020 and February 2021 were described as non-variant of concern, the Alpha period ran from March to June and the Delta period was in July.

‘Our study shows that samples from individuals infected with the Delta variant harbour about 4-fold higher loads of SARS-CoV-2 compared to individuals that are infected with non-VOC or the Alpha variant, which is significantly lower than previously reported,’ the researchers said.

‘We can conclude that the Delta variant is more contagious than the Alpha variant, but not to the extent that was recently suggested,’ said Paul Savelkoul, research leader and head of the microbiology lab in Maastricht.

‘It is very important that the testing as it is now being maintained is maintained,’ he said. ‘In this way, it can be established in good time whether changes are taking place in the form of new, for example, more pathogenic variants and whether the virus continues to proliferate in the population.‘

The complete research can be read on academic website Research Square.